I've seen some movies and shit on it. It really looks like something you need an instructor to learn. I do however, know that they do a lot of one-legged squats(pistols) and one-armed pushups, and that a lot of the technique supposedly stems from breath control.
I would be wary of Systema were I you. I tend to get suspicious of any art making special forces claims, some even spout some shit about it going all the way back to the bogatyr which were kind of an early knight. If you are interested in Russian martial arts look into sambo, particularly combat sambo as you will get a good all around skill set out of it. Of course if you can find a Systema school in your area check them out, if they train hard and spar in a reasonable fashion I'm sure you could learn something useful, just don't fall into the uber deadly secret army style trap.
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